I/O from XDMF/HDF5 files in dolfin-x

[dokken]

@dokken

This means that there is no direct mapping between the mesh generated with create_unit_square and the one read from file.

@marchirschvogel

I would expect setting a function, writing it, and reading it back in again should yield the same, but this MWE is failing in my case (only tested in serial):

See my comments in the previous posts.
If you simply want to read and write the function data in the same script, you could use something alot more lightweight (as then the number of processes are the same, all the data is local). I would use either the adios2 python interface or just h5py to read and write local chunks of the u.x.array to and from file.